Search results for "ritmi"

Esposizione a campi elettromagnetici a bassa frequenza (ELF) in ambito occupazionale e nella popolazione generale

2011

Scopo del presente lavoro è quello di verificare l’eventuale riscontro di alterazioni della frequenza cardiaca e del ritmo cardiaco in un campione di soggetti esposti professionalmente a campi elettromagnetici, nello specifico lavoratori di centrali elettriche e sottostazioni, afferenti presso l’ambulatorio di cardiologia della Sezione di MDL dell’AOUP di PA, posti a confronto con soggetti di pari età e sesso non esposti al fattore di rischio considerato. I dati raccolti sono stati messi in relazione ai rilievi ambientali dei campi elettromagnetici a bassa frequenza effettuati dall’ARPA Sicilia (1). Sono stati quindi analizzati i risultati ottenuti nelle due popolazioni in esame al fine di …

Experimental Study of the Effects of EIPA, Losartan, and BQ-123 on Electrophysiological Changes Induced by Myocardial Stretch

2015

[ES] Introducción y objetivos Se han implicado diversos mecanismos en la respuesta mecánica al estiramiento miocárdico, que incluyen la activación del intercambiador Na+/H+ por acciones autocrinas y paracrinas. Se estudia la participación de estos mecanismos en las respuestas electrofisiológicas al estiramiento agudo miocárdico mediante el análisis de los cambios inducidos con fármacos. Métodos Se analizan las modificaciones de la fibrilación ventricular inducidas por el estiramiento agudo miocárdico en corazones de conejo aislados y perfundidos utilizando electrodos múltiples epicárdicos y técnicas cartográficas. Se estudian 4 series: control (n = 9); durante la perfusión del antagonista d…

On the statistics of pairs of logarithms of integers

2022

We study the statistics of pairs of logarithms of positive integers at various scalings, either with trivial weights or with weights given by the Euler function, proving the existence of pair correlation functions. We prove that at the linear scaling, which is not the usual scaling by the inverse of the average gap, the pair correlations exhibit a level repulsion similar to radial distribution functions of fluids. We prove total loss of mass phenomena at superlinear scalings, and constant nonzero asymptotic behavior at sublinear scalings. The case of Euler weights has applications to the pair correlation of the lengths of common perpendicular geodesic arcs from the maximal Margulis cusp nei…

Evolutionary design optimization with Nash games and hybridized mesh/meshless methods in computational fluid dynamics

2012

On the use of approximate Bayesian computation Markov chain Monte Carlo with inflated tolerance and post-correction

2020

Approximate Bayesian computation allows for inference of complicated probabilistic models with intractable likelihoods using model simulations. The Markov chain Monte Carlo implementation of approximate Bayesian computation is often sensitive to the tolerance parameter: low tolerance leads to poor mixing and large tolerance entails excess bias. We consider an approach using a relatively large tolerance for the Markov chain Monte Carlo sampler to ensure its sufficient mixing, and post-processing the output leading to estimators for a range of finer tolerances. We introduce an approximate confidence interval for the related post-corrected estimators, and propose an adaptive approximate Bayesi…

Causal Effect Identification from Multiple Incomplete Data Sources: A General Search-Based Approach

2021

Causal effect identification considers whether an interventional probability distribution can be uniquely determined without parametric assumptions from measured source distributions and structural knowledge on the generating system. While complete graphical criteria and procedures exist for many identification problems, there are still challenging but important extensions that have not been considered in the literature. To tackle these new settings, we present a search algorithm directly over the rules of do-calculus. Due to generality of do-calculus, the search is capable of taking more advanced data-generating mechanisms into account along with an arbitrary type of both observational and…

The Max-Product Algorithm Viewed as Linear Data-Fusion: A Distributed Detection Scenario

2019

In this paper, we disclose the statistical behavior of the max-product algorithm configured to solve a maximum a posteriori (MAP) estimation problem in a network of distributed agents. Specifically, we first build a distributed hypothesis test conducted by a max-product iteration over a binary-valued pairwise Markov random field and show that the decision variables obtained are linear combinations of the local log-likelihood ratios observed in the network. Then, we use these linear combinations to formulate the system performance in terms of the false-alarm and detection probabilities. Our findings indicate that, in the hypothesis test concerned, the optimal performance of the max-product a…

Surrogate outcomes and transportability

2019

Identification of causal effects is one of the most fundamental tasks of causal inference. We consider an identifiability problem where some experimental and observational data are available but neither data alone is sufficient for the identification of the causal effect of interest. Instead of the outcome of interest, surrogate outcomes are measured in the experiments. This problem is a generalization of identifiability using surrogate experiments and we label it as surrogate outcome identifiability. We show that the concept of transportability provides a sufficient criteria for determining surrogate outcome identifiability for a large class of queries.

Attēlu fona modelēšanas algoritmi

2019

Datorredzes izpētes laukā ir sastopami dažādi izacinājumi, kas atstāj iespaidu uz fona modelēšanas algoritmu darbību. Piemēram, apgaismojuma maiņas, dinamisks fons un ēnas. Pie fona modelēšanas izaicinājumiem var pieskaītīt arī ar video filmēšanas tehniskajām grūtībām radītios izaicinājumus, pie kuriem pieder arī kompresijas artefakti. Taču, ir jāatzīmē, ka kompresijas artefaktu atstātāis efekts uz fona modelēšanas algoritmiem ir maz pētīts. Šī darba ietvaros tika pētīta kompresijas artefaktu atstātā ietekme uz dažiem fona modelēšanas algoritmiem. Izpētei tika izvēlēti divi algoritmi Mixture of Gaussians (MOG) un K-Nearest Neighbours (KNN), kas tika darbināti uz CDNET video datu kopas ar un…

Comparison of Internal Clustering Validation Indices for Prototype-Based Clustering

2017

Clustering is an unsupervised machine learning and pattern recognition method. In general, in addition to revealing hidden groups of similar observations and clusters, their number needs to be determined. Internal clustering validation indices estimate this number without any external information. The purpose of this article is to evaluate, empirically, characteristics of a representative set of internal clustering validation indices with many datasets. The prototype-based clustering framework includes multiple, classical and robust, statistical estimates of cluster location so that the overall setting of the paper is novel. General observations on the quality of validation indices and on t…